Wall's aptitude for engineering won him an apprenticeship with
Vickers Armstrong at the age of sixteen in the town of Crayford where he was born. He served in the army with the Royal Electrical and Mechanical Engineers in early 1950s and there became interested in telescopes and
astronomy. He went on to become a design engineer at
Vickers and, while working there in 1969, came up with the idea for an accurate mechanically simple
eyepiece mount for amateur telescopes, the
Crayford focuser. He is also known for designing
dialyte based
refracting telescopes, coming up with the
Zerochromat retrofocally corrected refractor, including a folded 30-inch f/12 version he built in 1999. This
refracting telescope is the largest ever built by an individual and the eighth-largest refractor ever built. Wall died on 27 January 2018. ==Inventions==